With a belt retractor that has a belt spool mounted rotatably in a frame and a drive motor coupled to the belt spool via a reduction gear, the drive motor can assume the retraction function, which is performed by a winding spring in conventional belt retractors. By appropriately actuating the drive motor, the belt force can be varied corresponding to the operating state of the belt retractor. In the contact area, the belt force is reduced in order to improve the wearing comfort; in the retraction area, the belt force is increased in order to ensure complete winding up of the seatbelt. Moreover, the drive motor can carry out a pretensioning of the seatbelt in order to prepare a possibly necessary tensioning of the seatbelt by means of a pyrotechnical belt tensioner. A direct emergency tensioning by the drive motor alone has not yet been considered as an option since the technology available can achieve neither the high belt forces nor the short response times that are necessary in such cases. Thus, for the belt tensioning, it is generally required that 120 mm of belt slack to be retracted within less than 30 ms. The normally used pyrotechnical belt tensioners generate belt forces of over 1000 N. Available electric motors that would be able to generate similarly high forces are too large and too heavy to reach the necessary speed within the short period of time of less than 30 ms.